Truck hoist mechanism



May a, 1947.-

E. J. ABBE TRUCK HOIST MECHANISM Filed 001;. 8, 1945 2 Sheets-Sheet lINVENTOR fan ,4? J 4555 Y 7, M 7 ATTORNEYS May 6, 1947 J ABBE I2,419,938

TRUCK HOIST MECHANISM Filed Oct. 8, 1945 2 Sheets-Sheet 2 @u a zafgATTORNEYS FIG. 5

Patented May 6, 1947 Edward J. Abbe, Cleveland Heights, Ohio, assignorto The Elwell-Parker Electric Company,

Cleveland, ()hio,

a corporation oi Ohio I Application October 8, 1945, Serial No. 620,917

(Cl..1&'7--9) 4 Claims.

The present invention relates to an industrial truck, and moreparticularly to a hoist mechanism for an industrial truck.

Industrial trucks have been provided having a vertically extendingframework for guiding an elevator vertically, which elevator is raisedand lowered by a hydraulically operated piston. The framework comprisestwo spaced upright members suitably tied together and which membersreceive therebetween a second framework adapted to telescope therewithso that the elevator could be raised relatively high although theframework would normally be compact. The

piston, during its upward stroke, would engage thetelescoped frameworkand raise it along with the elevator to provide an extended guide forthe elevator. The framework would descend by gravity, and at times itwould stick in the raised position after. the piston had recededdownwardly, and this. wouldv result in improper operation of theelevator and there was also the danger of injury to the mechanism by thesudden release of the elevated framemember.

An object of the present invention, therefore, is to. provide mechanismfor positively lowering the raised framework to prevent sticking thereofin the raised position- In carrying out the invention, I providemechanism for latching the piston with the telescoped. frame memberwhereby the piston is positively connected with the framework throughoutthe range of movement of the framework. This mechanism. is adapted torelease the piston from the telescoping frame member when the. framereaches its lowermost position so that the piston may descend below the.point. at which it engages the frame.

Other objects and advantages of the invention will be apparent from thefollowing description of the preferred form of the embodiment of theinvention, reference being had to the accompanyingdrawings wherein.-

Fig- 1 shows an industrial truck including an elevator mechanism whichembodies the invention;

, Fig- 2 is a view taken substantially on. line 2--'2 of Fig. 1;

Fig. 3 is.- a view in section, but on a larger scale, taken.substantially on line 3-3 of Fig. 2;

Fig. 4 is a view similar to that of Fig. 3, but showing the parts of theelevator mechanism in a different. position; and

Fig. 5.is.a view taken substantially on line 5-5 of Fig. 3.

Referring to the drawings, I have shown an industrial truck, illustratedgenerally at Ill, which is the type commonly used in factories, ware-ihouses and the like for transporting material from one location toanother. Although theirrvention may be used in connection with anysuitable industrial type of industrial truck, the truck shown includesthe running wheels l i: and power mechanism enclosed under the hood 2;The power mechanism may be either electric motors driven by batteriescarried by the truck. or it may be a gasoline engine, for example;

At the forward end of the truck there is averticall-y extendingframework, indicated generally at 35, which framework includes a mainstructure it and a structure it adapted to telescope in the mainstructure. This framework provides a guide for an elevator platform i8,which elevator is adapted to move vertically along the framework and tosupport loads to be carriedby the truck. The elevator i8 is adapted tobeelevated and lowered by a suitable hydraulic mechanism which includes acylinder at and a piston rod 2t, which piston rod is actuated by apiston inthe cylinder. An oil pump and suitable valve mechanism, notshown, are provided whereby oil may be forced into either side of thepiston for causing raising and lowering of thepiston rod. A head 22 iscarried by the end of the piston rod 2i and a transversely extendingaxle 23- is carried by the head 22, which axle supports sprockets 2tmounted at opposite ends thereof. Twoc'hains 25 are threaded on the"respective sprockets, one end of the chains being secured to across-member 2? of the framework it by suitable clamp and bolt arrangements shown at 28, and the opposite ends of the chains beingsimilarly attached to'the ele'- vator [81' Thus, when the piston israised and lowered the elevator !'8' will be raised and loweredcorrespondingly.

The frame structure It comprises two vertically extending members 38 and3'! which are spaced apart and pivotally connected with the frame of thetruck it in a suitable manner, not shown, and these members are tiedtogether. by crossmembers Hand-32. The members'SG and-3E are preferablychannel-shaped with the opensides thereof facing one another forreceiving, respectively.two I-beams 35 and 36 of the frame'structurel'T, which I-beams' form the structure i'l'. The beams 35 and 3b aresecured together at their upper ends by an inverted channel member 37.Preferably, the beams 35 and Sdform a guide for rollers, not shown,attached to the elevator it, which rollers cooperate with the guide formoving the elevator in a vertical path. When" the piston rod 21- andframe-structure I 1 are in their lowermost position, the head 22 of thepiston rod will be several inches below the cross-beam 31 of framestructure l1. Thus, the framework I is compact when the elevator islowered so that the truck may be driven through relatively low clearancepassages, but, when desired, the frame can be extended considerably forraising the load-carrying elevator It to a high loading or unloadingpoint.

Preferably, the support structure |5 may be moved forwardly andrearwardly about its pivot by suitable mechanism, indicated generally at40, for providing greater maneuverability of the loads carried by theelevator.

The structure thus far described is well known, and it may be fabricatedaccording to standard practices. 7

Referring more particularly to Figs. 3, 4 and 5, I have provided meansfor locking and unlocking the head 22 of the piston rod 2| with theframe structure H as the piston rod engages and disengages the framestructure in its ascent and descent. This locking means is preferablyformed by providing the head 22 of the piston rod 2| with an upwardlyextending projection 4|, which projection has a flat top that is adaptedto engage the underside of the inverted channel 31 when th piston rod ismoved vertically, and a curved, downwardly facing surface 42 is formedin one side of the projection 4|, which surface is adapted to cooperatewith a latch member 43 for locking the piston rod with the framestructure H.

The latch 43 is pivoted at 44 by trunnions formed thereon which extendthrough openings formed through spaced blocks 45 that are welded to themember 31. The lower portion of the latch 43 is formed to provide asurface that extends downwardly and inwardly, as indicated at 43, andthe upper portion of the latch 43 is provided with a rounded portion 41that is complementary to the surface 42 on the projection 4|. The latch43 is urged clockwise about its pivot, as viewed in Figs. 3 and 4, by aspring 48, the ends of which spring react against a downwardly extendingflange of the channel member 31 and the lower portion of the latch 43,as may be seen from the drawings. Thus, the latch 43 will normally tendto urge the upper portion 41 thereof beneath the surface 42 of the head22 to thereby latch the piston rod 2| to the frame structure H in such amanner that the piston rod cannot move downwardly without also movingthe frame structure.

Means are provided for operating the latch to release the piston rod 2|from latch 43 when the structure |1 reaches its lowermost position, andin the embodiment shown this means comprises a wedge-shaped cam member50, welded or otherwise attached to the cross-member 32 of the framestructure It, which cam member has a sloping surface 5| in alignmentwith the inwardly and downwardly curved portion 46 of the latch 43. Thecam 50 is so shaped and positioned that, as the frame structure H islowered the surface 5| thereof is in alignment with the curved portion46 of the latch 43 and the cam will cause the latch 43 to rotatecounter-clockwise and thereby move the latch from beneath the surface 42of the head 22. Thus, the piston rod is released from the framestructure at that point and it may continue further downward movement,as clearly illustrated in Fig. 3.

When the piston rod is moved vertically, it engages the channel 31, andas it raises the structure |1 upwardly, the sloping cam surface 5|permits the latch 43 to be rotated clockwise and 4 beneath the surface42, as shown in Fig. 4, thereby latching the head 22 to the structure|1.

Preferably, I have provided guide blocks 55 welded to the channel member31 for retaining the head 4| in a position to be engaged by the latch,and the lower corner of the blocks 55 are beveled as at 56 and the edge51 of the head 4| is also beveled for guiding the head 4| into place.The latch '43 is recessed'for receiving one of the guide blocks 55.

It will be seen that by my invention I have provided an extremely simpleand efficient mecha nism for assuring the proper lowering of theelevator guide structure so that positive operation of the structure maybe had while allowing for full scope of movement of the elevator pistonrod.

Although I have described but one form of the invention, it is to beunderstood that other forms may be adopted, all falling within the scopeof the claims which follow.

I claim:

1. In an industrial truck, an upright support for guiding a platformvertically, said support including two sections, one slidable verticallyrelative to the other; a platform movable along said support; a, pistonmovable vertically and engageable with said one section for moving thelatter and for raising said platform; means forming a latchingconnection between said piston and said one section whereby when thepiston is being lowered said piston lowers said one section; and meansfor actuating the first mentioned means for releasing said piston andsection when said section is lowered to a predetermined position.

2. In an industrial truck, an upright support carried by the truck; asecond upright support telescoping with the first mentioned upright andmovable longitudinally relative to said first mentioned upright; aload-receiving platform; means on said uprights and platform for guidingsaid platform vertically; means for raising said platform verticallyincluding, a piston adapted to travel adjacent said second upright whensaid upright is moved longitudinally relative to the first mentionedupright; a latch member and a catch member, one of said members beingmounted on said piston and the other of said members being mounted onsaid second upright, said latch being engageable with said catch forinterlocking said piston and second uprightjand means for actuating saidlatch member when said piston and second upright move to a predeterminedposition for releasing said piston and second upright.

3. In an industrial truck, an upright support carried by the truck, asecond upright support telescoping with the first mentioned upright andmovable longitudinally relative to said first mentioned upright; aload-receiving platform; means on said uprights and platform for guidingsaid platform vertically; means for raising said platform verticallyincluding, a piston adapted to travel adjacent said second upright whensaid upright is moved longitudinally relative to the first mentionedupright; a latch member and a catch member, one of said members beingmounted on said piston and the other of said members being mounted onsaid second upright, said latch being engageable with said catch forinterlocking said piston and second upright, and a cam member disposedon the first mentioned upright for engagement by said latch memberwhereby said latch member is disengaged from said catch when said secondupright is moved to a predetermined position.

presenting a surface facing upwardly; a catch member carried by saidpiston, said catch presenting a surface facing downwardly for engagementwith the surface of said latch; means resiliently urging said latch to aposition for engagement with said clutch; and a cam engageable by saidlatch and adapted to rotate said latch out of engagement with said catchwhen the said second upright is lowered to a predetermined 10 position.

EDWARD J. ABBE.

